Common law - judge made law, and relevant as it forms half the basis of our justice system. Importart cases such as Mabo and Wik encouraged lawmakers in parliament to statutise these laws, and common law is also the branch of law which gave us terms such as residual freedom - or the freedom to do whatever as long as we did not break the law.
Statute law - parliament made law, this forms the other major half of domestic law. Laws such as the Anti-Discrimination Act, Sex Discrimination Act and many others have formed the backbone of Australian society in mirroring its ethics and values, and has also determined what exactly is a crime and the like.
International law - via treaties and agreements, this can influence Australian law, such as the International Convention on the Rights of the Child, or Universal Declaration of Human Rights and the like. Things such as the Kyoto Protocol has encouraged Australia to be more proactive environmentally, and especially now, more environmental laws encouraged by the protocol are popping up.